1. Field of the Invention
This invention relates to catalysis. In one aspect, the invention relates to the oxidation of isobutyraldehyde to methacrylic acid while in another aspect, the invention relates to the use of various oxide compositions as catalysts for this oxidation reaction.
2. Description of the Prior Art
The oxidation of isobutyraldehyde to methacrylic acid is known. German patent application 3,001,911 to Matsumotor et al. teaches this reaction in the vapor phase using a heteropolyacid or a mixture of a heteropolyacid and its salt as a catalyst with the general formula: EQU Mo V P X Y O (II)
where X is anyone of a number of different elements including copper, tin, thorium, etc, and Y (which is optional) is one of potassium, rubidium, cesium or thallium. Other teachings include Japanese Pat. No. 3,082,715, Japanese applications 78:124,210; and 75:149,611; 72:14,085, 75:12,011, 71:28,001, 78:124,211 and 48:078,112, and U.S. Pat. No. 4,146,574. While all of these teachings show the manufacture of methacrylic acid from isobutyraldehyde, some are betters than others. Indeed of the cited references, only German patent application No. 3,001,911 and Japanese patent applications 78:124,210; 75:149,611 and 78:124,211 show methacrylic acid as the dominant product and of these, only the German patent application reports as least one instance of methacrylic acid being produced in excess of 60% yield. As such, the art has room for new and more efficient processes.